So I looked through the gameindustry monthly articles and could only find two cases where monthly digital and physical splits were given for games.

RE8:
Physical [80:20]
All [65:35] (58:31:11)(PS:XB:PC)

FC6:
Physical [70:30]
All [58:42]

Avg digital ratio in increments of 10% (60%,70%,80%,90%).
Total software sales split using above increments:
RE8 - [55:45] , [59:41] , [61:39] , [63:37]
FC6 - [50:50] , [53:47] , [55:45] , [57:43]

We know in 2020 the digital split between PS and XB was [61:39]. We know Xbox was disproportionately increased its digital share. Lets assume [55:45] 2021.
Many months this year have digital to physical software sold ratios of [63:37]. Unfortunately this includes PC, so physical should be bigger, but SW does not give digital and accounts for 20% of all software sales. Assuming PC accounts for 10% of digital sales (RE8 had this), we get [77:23].
We can roughly see an avg of [75:25] for PS:XB physical 2021.

In summary, our assumptions:
- 2021 PS:XB digital software split = [55:45]
- 2021 PS:XB physical software split = [75:25]
- 2021 digital to physical split = [77:23]

0.77(55) + 0.23(75) = 60
Therefore [60:40] can be estimated as the total software split PS:XB UK.
The hardware split for PS4/XB1 was [56:44].
As you can see, Playstation is getting a disproportionate amount of software sales in XB's 2nd biggest market.

Ubisoft global splits (inc. digital)
2020: [63:37]
2021: [66:34]

Region split (EU:US:RotW)
2021: [32:50:18]
Some interesting things we can work out from here with this [1]. Assuming the regions have the same software tie ratio, UK accounts for 20% of PS4 software sales and 48% of XB software sales in EU. Therefore the UK accounts for (using FC6 splits) 0.58(20) + 0.42(48) = 31.7% of Ubi sales in EU. So we have [22.4, 9.6, 50, 18].

Now we can estimate the Ubi split in (EU + RotW)
0.66 - [0.5(54) + 0.096(58)] = 84

Hardware split in 2019 [1]:
- US [54:46]
- UK [56:44]
- EU [81:19]
- AS (JP,SK,TW) [98:02]

TLDR:

- PS has 60:40 lead on XB in UK despite hardware split being 56:44
- A western game has 66% console sales on Playstation. This could be 75-85% for JP games.
- This could mean Playstation has a whopping 84:16 split on western software in EU+RoTW. This could be 90%+ for a JP game.
- MHW, perhaps an extreme due to being Asia centric where XB is 0, has 84% of console sales on Playstation.

CONCLUSION: Playstation is, imo pretty safely, getting 70-75% of all software sales in PS/XB games.

[1] https://www.resetera.com/threads/hardware-and-software-sales-2019-in-many-countries.277262/

Hardware split in the UK actually is ~60:40 for PS5:XBS.

56:44 is for PS4:XB1.

Where is the source for the PS5:XBS numbers?

Hardware split in the UK actually is ~60:40 for PS5:XBS.

So I looked through the gameindustry monthly articles and could only find two cases where monthly digital and physical splits were given for games.

RE8:
Physical [80:20]
All [65:35] (58:31:11)(PS:XB:PC)

FC6:
Physical [70:30]
All [58:42]

Avg digital ratio in increments of 10% (60%,70%,80%,90%).
Total software sales split using above increments:
RE8 - [55:45] , [59:41] , [61:39] , [63:37]
FC6 - [50:50] , [53:47] , [55:45] , [57:43]

We know in 2020 the digital split between PS and XB was [61:39]. We know Xbox was disproportionately increased its digital share. Lets assume [55:45] 2021.
Many months this year have digital to physical software sold ratios of [63:37]. Unfortunately this includes PC, so physical should be bigger, but SW does not give digital and accounts for 20% of all software sales. Assuming PC accounts for 10% of digital sales (RE8 had this), we get [77:23].
We can roughly see an avg of [75:25] for PS:XB physical 2021.

In summary, our assumptions:
- 2021 PS:XB digital software split = [55:45]
- 2021 PS:XB physical software split = [75:25]
- 2021 digital to physical split = [77:23]

0.77(55) + 0.23(75) = 60
Therefore [60:40] can be estimated as the total software split PS:XB UK.
The hardware split for PS4/XB1 was [56:44].
As you can see, Playstation is getting a disproportionate amount of software sales in XB's 2nd biggest market.

Ubisoft global splits (inc. digital)
2020: [63:37]
2021: [66:34]

Region split (EU:US:RotW)
2021: [32:50:18]
Some interesting things we can work out from here with this [1]. Assuming the regions have the same software tie ratio, UK accounts for 20% of PS4 software sales and 48% of XB software sales in EU. Therefore the UK accounts for (using FC6 splits) 0.58(20) + 0.42(48) = 31.7% of Ubi sales in EU. So we have [22.4, 9.6, 50, 18].

Now we can estimate the Ubi split in (EU + RotW)
0.66 - [0.5(54) + 0.096(58)] = 84

Hardware split in 2019 [1]:
- US [54:46]
- UK [56:44]
- EU [81:19]
- AS (JP,SK,TW) [98:02]

TLDR:

- PS has 60:40 lead on XB in UK despite hardware split being 56:44
- A western game has 66% console sales on Playstation. This could be 75-85% for JP games.
- This could mean Playstation has a whopping 84:16 split on western software in EU+RoTW. This could be 90%+ for a JP game.
- MHW, perhaps an extreme due to being Asia centric where XB is 0, has 84% of console sales on Playstation.

CONCLUSION: Playstation is, imo pretty safely, getting 70-75% of all software sales in PS/XB games.

[1] https://www.resetera.com/threads/hardware-and-software-sales-2019-in-many-countries.277262/

Suprised Switch version of GTA managed 13% considering all the issues for it.